1. Field of the Invention
This invention relates generally to hydrogen electrochemical systems. In particular, this invention relates to a unique, compact hydrogen electrochemical system, especially a system for producing greater than about 100 standard cubic feet per hour (scfh) hydrogen or a fuel cell system for generating greater than about 1 kW (kilowatt) of electricity, including the attendant enclosures, ventilation and thermal conditioning equipment, allowing for adequate isolation and operation of the generator.
2. Brief Description of the Related Art
Hydrogen, under ordinary conditions, is a colorless, odorless, tasteless, non-toxic gas comprised of diatomic molecules. There are many industrial uses of hydrogen including manufacturing ammonia and methanol, desulfurization of petroleum products, hydrogenation of fat and oils, production of electricity, and reduction of metallic oxide ores. Hydrogen, a flammable gas that diffuses rapidly in air, has a flammable range of approximately 4 percent to 94 percent by volume (vol. %), in air, at atmospheric pressure. Spark temperatures as low as 500.degree. C. will initiate explosion of a hydrogen-air mixture. Consequently, the production and use of hydrogen is tightly controlled and regulated.
Laboratory scale, less than about 1 scfh hydrogen, are comparatively simple and compact hydrogen generating systems. In the commercial environment, however, strict regulations governing the production of hydrogen, in amounts exceeding about 100 scfh for example, has increased the complexity, expense, and space requirement for these systems.
Hydrogen electrochemical systems of the prior art, including water electrolyzer systems for example, are commercially available in open metal frame structures. Systems of moderate and large capacity (greater than about 100 scfh of hydrogen) are typically integrated with separate power, control, ventilation, and heat exchange equipment when installed in a building or facility as a hydrogen generating system. Due to the risk of an explosion of any uncontained hydrogen gas, the National Electric Code (Article 501), requires the use of explosion-proof methods when employing electrical equipment in hazardous environments. These methods include the use of explosion-proof housings, components, and certain energy limiting, "intrinsically safe", zener barrier devices, and often require housing of the generator and associated equipment in special ventilated buildings or weatherized structures.
The hydrogen generator systems of the prior art, which require explosion proof components and/or specialized housing, suffer from the fact that these components are more costly to procure and install, and typically require significantly higher cost and effort to deploy than their non-explosion proof commercial counterparts.
What is needed in the art is a compact, reduced cost, hydrogen electrochemical system configuration which meets the applicable codes and regulations, and can be utilized in hydrogen generating systems and various fuel cell systems.